1. Field of the Invention
The present invention relates to a signal processing apparatus, an information processing apparatus, a multilevel coding method, and a data transmission method.
2. Description of the Related Art
Most information processing apparatuses such as mobile phone and notebook personal computer (hereinafter, a notebook PC) use a movable member for a hinge portion connecting a main body to be operated by a user and a display portion on which information is displayed. However, a large number of signal lines and power lines pass through the hinge portion, and a method for maintaining reliability of the wiring is desired. Reducing the number of the signal lines passing through the hinge portion comes first to mind. Therefore, data transmission processing between the main body and the display portion is made to be performed by using a serial transmission method instead of a parallel transmission method. When the serial transmission method is used, the number of signal lines is decreased.
In the serial transmission method, data is encoded and then transmitted. At that tune, for example, a Non Return to Zero (NRZ) coding scheme, a Manchester coding scheme, an Alternate Mark Inversion (AMI) coding scheme, or the like is used as the coding scheme. For example, JP-A-1991-109843 discloses a technology for transmitting data by using an AMI code, which is a representative example of a bipolar code. The patent document also discloses a technology according to which a data clock is transmitted after being expressed by an intermediate value of a signal level, and the receiving side regenerates the data clock based on the signal level.